I knw the Greddy 15G comes with an internal wastegate. And I know that its a mechanical peice that controls the boost level. But can a turbo w/ an internal wastegate be converted to external wastegate? And do electronic boost controllers control the mechanical wastegate or do you have to have some sort of electronic wastegate to use a boost controller?
What is the range that the stock internal wastegate on the 15G can run boost wise? 4-7 psi or so? After that you need some other wastegate or what? I'd like to be able to install a Greddy kit and eventually upgrade to 10 psi MAX while using as few electronic/computer controlled things possible, so are there mechanical boost controllers that can be used?
Thanks in advance for putting up with my questions - theres a lot to learn.
-Ryan

You set your GReddy wastegate between 6 and 7 psi and then add a boost controller which limits the compressor feed to the actuator until you get to your setting where it allows the passage of air to blow it open. Would not be necessary to convert to an external wastegate and would add a lot of expense.

Not completely sure if I follow what you explained - it makes sense but it sounds like you must have a wastegate and a boost controller for the system to work. Greddy kits only come with the internal wastegate - no boost controller, so does the existing wastegate do all the work of venting the air when it reaches the set psi without the need for a boost controller? If so, when does it become necessary to add a boost controller?

On a slightly different note, are internal wastegates replaceable? For instance, if you wanted to buy a different turbo and found one on ebay that was listed as having a 12 psi wastegate on it, would that mean you can adjust that wastegate at anything up to that psi, or would you have to change it out if you don't want to run that high of a boost level?
-Ryan

an internal wastegate can be converted to external wastegate but its not necessary,
an electronic boost controller controlls regular mechaical internal or external wastegate
you can get a boost controller to raise or lower a stock wastegate pressure (so you can keep the stock wastegate)
you dont need a boost controler for the greddy the stock wastegate
if you want more boost you leave the wastegate just add a boost controller.
if youre interested i have an electronic profed b, im selling in the parts section.

Without a boost controller added, is 6 psi the most you can dial into the 15G's wastegate?
If so, to reach 7 or 8 psi... or more... one would have to get either a mechanical or electronic boost controller that is capable of the boost you do want and just... what? 'plug' it into the existing wastegate?
I'm sure its more complicated than that but essentially it just hooks up to the wastegate?

Wastegates differ in the amount of adjustment you can get out of them. Mine went to 9psi before I needed to add a controller. Add an MBC in the line and you can take it higher. You do not NEED electronic boost control.